Aerosols are used in the food industry, for example for sterilising packaging.
In metering devices for dispensing an aerosol having a defined liquid concentration, flow measurements of the liquid are frequently carried out and the opening time of a switching valve is adjusted to the determined flow values.
Hydrogen peroxide solutions, which are usually used for sterilisation purposes with a concentration of 35%, tend to decompose at least partially into oxygen and water, especially at such high concentrations, so that apart from the liquid phase, a gaseous phase will always be present as well.
This gaseous component can have an adverse effect on the flow measurement of the liquid, so that the metering will subsequently become inaccurate and unreliable. However, it is especially in the food industry that very accurate metering processes are necessary, because it has to be avoided at all costs that either in the case of an overdosage food is contaminated with chemicals such as disinfectants or that in the case of an underdosage the packaging is not sterile and as a result, food will become infested with germs.
It is therefore the object of the invention to provide a metering unit that does not have these disadvantages and that allows an exact metering of an aerosol to be accomplished.